Character Walk Cycle is not working properly
It's a names problem: as you can see the paste function is working for all "central bones", while the lateral ones need to find their side counterparts, and they can recognize them only with the right kind of suffix used for L/R.

For example if you rename your LeftFoot as Foot.L and your RightFoot to Foot.R, everything works properly for these two bones also.

Examples of valid separators:

(nothing): handLeft –&gt; handRight
_ (underscore): hand_L –&gt; hand_R
. (dot): hand.l –&gt; hand.r
- (dash): hand-l –&gt; hand-r
 (space): hand LEFT –&gt; hand RIGHT


The Blender Manual states that also your way, with the complete Left or Right word before the name, should work, but it doesn't: you have to rename all your bones with an end L/R suffix.